Redrawn capillary imaging reservoir

ABSTRACT

Methods and apparatus for depositing a high density biological or chemical array onto a solid support. Specifically, the apparatus is made up of a plurality of open ended channels collectively forming a matrix. The matrix has been redrawn and cut such that the pitch of the channels on the loading end is larger than the pitch of the channels on the liquid delivery end. The upper portion of each channel serves as a reservoir, while the opposing end, which has been formed by the redrawing process, is diametrically sized such that liquid in the reservoir is retained by capillary pressure at the delivery end. At any point along the height of the capillary reservoir device, all cross-sectional dimensions and areas are uniformly reduced. In other words, the on-center orientation of any two channels, also referred to as the pitch between 2 channels, measured as a function of the diameter of any cross section, is constant throughout the structure. The liquid within the channels is either printed directly from the tool onto a substrate or transferred to a substrate by a typographical pin plate. In another embodiment, the device may be used in transferring sample between multiwell plates of different well density.

This application is a con of U.S. application Ser. No. 09/299,766 filedon Apr. 26, 1999 now U.S. Pat. No. 6,596,237 and claims the benefit bothof Provisional Application No. 60/091,707 filed on Jul. 3, 1998 and ofEuropean Application number 98401021.5 filed on Apr. 27, 1998, and a conof of, U.S. application Ser. No. 09/300,121 filed on Apr. 27, 1999 nowU.S. Pat. No. 6,350,618 and all of its ancestor applications, where U.S.application Ser. No. 09/300,121 claims the benefit both of ProvisionalApplication No. 60/091,707 filed on Jul. 3, 1998 and of EuropeanApplication number 98401021.5 filed on Apr. 27, 1998.

FIELD OF INVENTION

The invention relates to a device and method for the printing of highdensity arrays for use in biological and chemical assays as well as adevice that can be used in sample transfer between multiwell plates ofdiffering well density.

BACKGROUND OF INVENTION

Hybridization is a hydrogen- bonding interaction between two nucleicacid strands that obey the Watson-Crick complementary rules. All otherbase pairs are mismatches that destabilize hybrids. Since a singlemismatch decreases the melting temperature of a hybrid by up to 10° C.,conditions can be found in which only perfect hybrids can survive.Hybridization comprises contacting the strands, one of which is usuallyimmobilized on a solid support and the other usually bears aradioactive, chemiluminescent or fluorescent label, and then separatingthe resulting hybrids from the unreacted labeled strands by washing thesupport. Hybrids are recognized by detecting the label bound to thesurface of the support.

Oligonucleotide hybridization is widely used to determine the presencein a nucleic acid of a sequence that is complimentary to theoligonucleotide probe. In many cases, this provides a simple, fast, andinexpensive alternative to conventional sequencing methods.Hybridization does not require nucleic acid cloning and purification,carrying out base-specific reactions, or tedious electrophoreticseparations. Hybridization of oligonucleotide probes has beensuccessfully used for various purposes, such as analysis of geneticpolymorphisms, diagnosis of genetic diseases, cancer diagnostics,detection of viral and microbial pathogens, screening of clones, genomemapping and ordering of fragment libraries.

An oligonucleotide array is comprised of a number of individualoligonucleotide species tethered to the surface of a solid support in aregular pattern, each species in a different area, so that the locationof each oligonucleotide is known. An array can contain a chosencollection of oligonucleotides, e.g., probes specific for all knownclinically important pathogens or specific for all known clinicallyimportant pathogens or specific for all known sequence markers ofgenetic diseases. Such an array can satisfy the needs of a diagnosticlaboratory. Alternatively, an array can contain all possibleoligonucleotides of a given length n. Hybridization of a nucleic acidwith such a comprehensive array results in a list of all its constituentn-mers, which can be used for unambiguous gene identification (e.g., inforensic studies), for determination of unknown gene variants andmutations (including the sequencing of related genomes once the sequenceof one of them is known), for overlapping clones, and for checkingsequences determined by conventional methods. Finally, surveying then-mers by hybridization to a comprehensive array can provide sufficientinformation to determine the sequence of a totally unknown nucleic acid.

Oligonucleotide arrays can be prepared by synthesizing all theoligonucleotides, in parallel, directly on the support, employing themethods of solid-phase chemical synthesis in combination withsite-directing masks as described in U.S. Pat. No. 5,510,270. Four maskswith non-overlapping windows and four coupling reactions are required toincrease the length of tethered oligonucleotides by one. In eachsubsequent round of synthesis, a different set of four masks is used,and this determines the unique sequence of the oligonucleotidessynthesized in each particular area. Using an efficientphotolithographic technique, miniature arrays containing as many as 10⁵individual oligonucleotides per cm² of area have been demonstrated.

Another technique for creating oligonucleotide arrays involves precisedrop deposition using a piezoelectric pump as described in U.S. Pat. No.5,474,796. The piezoelectric pump delivers minute volumes of liquid to asubstrate surface. The pump design is very similar to the pumps used inink jet printing. This picopump is capable of delivering 50 microndiameter (65 picoliter) droplets at up to 3000 Hz and can accurately hita 250 micron target. The pump unit is assembled with five nozzles arrayheads, one for each of the four nucleotides and a fifth for deliveringactivating agent for coupling. The pump unit remains stationary whiledroplets are fired downward at a moving array plate. When energized, amicrodroplet is ejected from the pump and deposited on the array plateat a functionalized binding site. Different oligonucleotides aresynthesized at each individual binding site based on the microdropdeposition sequence.

Another approach using arrays is the pin dipping method for paralleloligonucleotide synthesis. Geysen, J. Org. Chem. 56, 6659 (1991). Inthis method, small amounts of solid support are fused to arrays ofsolenoid controlled polypropylene pins, which are sequentially dippedinto trays of the appropriate reagents. The density of the arrays islimited by this process.

Further approaches to forming an array involve taking presynthesizedoligonucleotide or cDNA sequences from separately prepared aqueousmixtures and transferring them to substrate either individually or insome small multiple. This may be accomplished for example by repeatedlycontacting a substrate surface with typographic pins holding droplets,using ink jet printing mechanisms to lay down an array matrix, or by useof a pen plotter. These printing processes are limited by the time andexpense required in transferring 10³ or greater different sequencemixtures onto defined positions on a substrate.

SUMMARY OF INVENTION

The present invention provides a capillary reservoir device and liquiddeposition tool and methods for depositing a high density biological orchemical array onto a substrate. The tool is made up of a plurality ofopen ended channels collectively forming a matrix. The matrix has beenredrawn and cut such that the pitch of the channels on the loading endis far larger than the pitch of the channels on the liquid delivery end.The upper portion of each channel serves as a reservoir, while theopposing end, which has been formed by the redrawing process, isdiametrically sized such that liquid in the reservoir is retained bycapillary pressure at the delivery end. At any point along the height ofthe capillary reservoir device, all cross-sectional dimensions and areasare uniformly reduced. In other words, the on-center orientation of anytwo channels, also referred to as the pitch between 2 channels, measuredas a function of the diameter of any cross section, is constantthroughout the structure. In another embodiment, a variation of thedevice of the present invention may be used in transferring samplebetween multiwell plates of different well density.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a three dimensional view of the device of the presentinvention.

FIG. 2 is a plurality of connected capillary tubes prior to redraw.

FIG. 3 is an illustration of the output end of the device being dippedinto a liquid reservoir in order to impart wettable characteristics tothe interior of the channels.

FIG. 4 is an illustration of the output end of the device being trimmedin order to expose a non wetting surface.

FIG. 5 is a three dimensional view of a preform block of material thatis being extruded through a honeycomb die.

FIG. 6 is a three dimensional view of an extruded block that has beensubsequently redrawn.

FIG. 7 is a side view of an extruded block that has been subsequentlyredrawn and is being subjected to a curing process.

FIG. 8 is a three dimensional view of a series of blocks that have beencut from the redrawn portion of the device of FIG. 7.

FIG. 9 is a three dimensional view of a block of FIG. 8 being sliced bya blade.

FIG. 10 is a three dimensional view of three high density array platesof the present invention.

FIG. 11 is an exploded view of a method of transfer of liquid samplefrom a multiwell plate to the capillary reservoir device of the presentinvention.

FIG. 12 is a three dimensional view of the device of FIG. 11 as used todeposit liquid sample to a receiving plate.

FIG. 13 is a cross sectional view of a capillary reservoir device of thepresent invention engaged by sealing means on both ends.

FIG. 14 is a cross sectional view of one channel of an embodiment of thecapillary reservoir device of the present invention.

FIG. 15 is a three dimensional view of a printing machine employing thecapillary reservoir device of the present invention.

FIG. 16 is a partial cross sectional view of the pin plate of FIG. 15contacting the output end of the capillary reservoir device.

FIG. 17 is a partial cross sectional view of the pin plate of FIG. 16after removal from the output end of the capillary reservoir device.

FIG. 18 is a partial cross sectional view of the pin plate of FIGS.15-17 after deposition of liquid material onto a substrate.

FIG. 19 is a cross sectional view of a printing tool of the presentinvention.

FIG. 20 is a cross sectional view of another embodiment of a printingtool of the present invention.

FIG. 21 is a cross sectional view of another embodiment of a printingtool of the present invention.

FIG. 22 is a partial cross sectional view of a slab of material whichwhen assembled with other like slabs forms a preform.

FIG. 23 is a partial cross sectional view of a plurality of slabs piledone upon another and prior to fusion.

FIG. 24 is a partial cross sectional view of a preform formed by fusingthe slabs of FIG. 23.

DETAILED DESCRIPTION OF THE INVENTION

Printing Tool

Glass and organic polymer redraw processes are well known and have beenused to form precision tubing, sheets and fiber bundles with complexcross sections. The present invention adapts the known redraw techniquein a unique way to form a container having an array of channels that canindividually deliver small volumes of liquid either onto a substrate, toa typographic pinplate, or into wells of a multiwell plate.

The redraw technique is instituted on a multi-celled extruded block,also referred to as a honeycomb substrate, or a collection of connectedcapillary tubes. An important aspect of the redraw technique is thatrelatively large glass or polymer structures having complexcross-sectional configurations, corresponding to complex cross-sectionalconfigurations of the final product may be easily formed to desireddimensions. During the redrawing or stretching process, allcross-sectional dimensions and areas are uniformly reduced while thepresent tolerance remains constant. Thus, for purposes of illustration,a 1 inch dimension having a tolerance of 1% e.g., ±0.01 inch, in a 10 to1 reduction results in a 0.1 inch dimension and a tolerance of ±0.001inch. A further 10 to 1 reduction results in a 0.01 inch dimension and atolerance of ±0.0001 inch.

In order to form a capillary reservoir device from glass, glass ceramic,or ceramic material, one must use a thermoplastic binder such asparaffin wax or a binder as described in U.S. Pat. No. 5,602,197,incorporated herein by reference, and combine it with an inorganicpowdered material, preferably PYREX 7761 powder with frit size centeredon 10 μm. This organic/inorganic mixture is then extruded through acounter rotating twin screw extruder, operated at room in temperature. Adie determines the dimensions of the extruded material. Preferably, a2-7 inch diameter, square or round channeled, monolithic honeycombpreform with 25-15 mil channel walls and 200-400 cells per square inchof frontal area results from the extrusion. The preform may be extrudedin either round, rectangular or square cross sectional shape. The crosssectional shape of the cells may be any shape as determined by the die.The organic binder must be carefully removed by heating slowly to asufficient temperature to cause volatilization and pyrolysis of theorganic binder. Slump and other distortion is avoided by carefulselection and control of the rheology, inorganic volume loading, andbinder pyrolytic/volatilization characteristics. After binder removal,the preform of packed particulates is then sintered to meld the powderparticles, while keeping the shape. In order to control wall sagging,sintering conditions must be closely monitored. The preform ispreferably sintered vertically in order to avoid distortion. Sinteringcondition for PYREX 7761 is approximately 675° C. for 1 hour. At thistemperature, glass particle binding occurs and 10-15% shrinkageuniformly occurs throughout the structure. What remains is a glass,glass ceramic, or ceramic depending on the sintering schedule and thecomposition of the original powder material. For use with thisinvention, preferably the firing schedule and powder composition shouldbe modified in such a way as to create substantially identical channelwalls of high density and no open porosity. The resulting honeycombblock has a plurality of parallel channels or cells extendingtherethrough. The block may be any length as determined by the point atwhich it is cut from the extruder.

EXAMPLE Extrusion and Sintering

Table 1 shows the composition of PYREX 7761 glass. The inorganic powderis made from PYREX 7761 cullet: crushed, magnetically separated, ballmilled (alumina), and ultrasonically screened (−325 mesh).

TABLE 1 Compound Weight Percent (%) SiO₂ 78.92 K₂O 2.76 B₂O₃ 18.27

Table 2 shows the batch composition of the extrudable mixture.

TABLE 2 Ingredients Weight (grams) PYREX 7761 powder 7938 Oleic Acid  80Dow F-40M METHOCEL  558 Water (DI) 1985

The inorganic powder, the METHOCEL, and the Oleic Acid are blendedtogether in a LITTLEFORD mixer, and then mulled together with the wateraddition in a LANCASTER mixer. The mix is then further mixed byevacuation and spaghetti extrusion (3 times). Finally, the batch isextruded through a die to be formed into a multi-celled preform which iscut from the extrudate, ready for sintering.

Table 3 shows the furnace schedule used to sinter the preforms. Thepreforms are vertically suspended during sintering to minimize bowing.

TABLE 3 Furnace Schedule 1) Room Temperature to 300° C. at 50° C./hr. 2)300° C. to 550° C. at 20°/hr. 3) 550° C. to 700° C. at 50° C./hr. 4)Hold at 700° C. for 2 hours. 5) 700° C. to Room Temperature (power off).

Once the preform is sintered, the resulting structure is heated andundergoes a redraw reduction. Redraw takes place approximately atapproximately 20° C. to 100° C. above the glass transformationtemperature. For PYREX 7761, the sintered block is reheated to 870° C.over approximately 1.5 hours, in order to reach a +/−20° C. temperatureuniformity within the section of the block to be stretched. The redrawprocess occurs in two steps; first, the block is arranged such that thechannels are aligned vertically; and, a portion of the extruded block isrestrained, while the weight of the structure is allowed to pull theunrestrained portion downward. Second, a constant force is applied tothe unrestrained portion to further facilitate the draw. Once theextruded block is stretched to a predetermined diameter, depending onthe cross sectional size requirement for the output end of the device,the process is stopped by temperature reduction. This annealing steppreferably occurs over one hour in which the temperature is dropped to20° C. As an example, for a 180 mm long cylindrical block having a 22 mmcross sectional diameter to be drawn to a cross sectional diameter of4.2 mm, the block must be drawn approximately 920 mm in length. It ispreferred that, after redrawing, the length of the capillary reservoirdevice be between 2 and 3 times the diameter of the block prior toredraw, in order to optimize the liquid retaining capillarycharacteristics of the individual channels.

In producing a bent reservoir device, as required in some embodiments,the drawn piece is maintained at a temperature of approximately 850° C.in the portion to be bent. The piece is removed from the oven and bentat the appropriate angle, 180° for example. After bending, the piece isplaced in an annealing oven in order to cool to room temperature withoutthermal stress.

After annealing to approximately 20° C. over the course of approximately1 hour, the piece whether bent or not, is cut on the reduced section ofthe block, which becomes the output end of the reservoir device, and mayalso be cut on the loading or input end by a diamond saw for example.The cutting is preferably performed under internal water flux in orderto prevent any glass chips or fragments from lodging in the channels.The output end of the piece can then be finished by successivelypolishing with 12 μm, 3 μm, 1 μm, and 0.3 μm grit polishing paper. Ifthe device is to be used in printing extremely low volume liquid drops,it is important to achieve a flatness of approximately ±2 μm across theoutput end of the device. The device may be further finished under firepolish at approximately 450° C. for one hour.

Optionally, when using a binder such as those disclosed in U.S. Pat. No.5,602,197, the option exists to redraw the preform after extrusion, butprior to binder removal and sintering. Redraw in this case is done as itwould be for a thermoplastic polymer; in that the preform, or thesection of the preform to be redrawn, is reheated to a softened orpartially melted state whereupon the preform is redrawn by stretching.An advantage of using this technique is that inorganic particulates canbe used that cannot be redrawn in the inorganic state, such as zirconia,alumina, etc.

In an embodiment in which a capillary reservoir device is made from athermoplastic polymer, the polymer is initially extruded through a twinscrew extruder and die operating at the melting temperature of thethermoplastic material, for example, polypropylene is extruded atapproximately 180° C. The target cell density and wall thickness issubstantially the same as the glass embodiment discussed above. Once theblock has been extruded, the polymer redraw is performed as above andmay require external heating of the structure, or the section to beredrawn, to 150° C., for example in polypropylene. The redraw may alsorequire internal heating of the polymer structure by means of forcedheated air, for example, in order to preclude any internal heatinggradient within the structure during redraw. Although the extrusion hasbeen demonstrated with a polyolefin, specifically, polypropylene, itshould be understood that any thermoplastic polymer, as recognized byone skilled in the art, may be used for this process.

Although a cylindrical extrusion is easier to perform in both powderedglass and plastic, a square or rectangular extrusion is preferred inorder create a tool capable of depositing a rectilinear array.

Both extrusion of the polymer and the powdered glass is ideallyperformed by a vertical extrusion process. Vertical extrusion helpsreduce problems of wall sagging due to gravitational effects. However, ahorizontal extrusion process may be preferred in a mass productionsetting.

Yet another option for drawing down an extruded cellular body is to fillin the open cells of an extruded preform with a molten wax that exhibitssimilar plastic properties to the wet batch when solidified. The cooledbody, consisting of the wet extruded cellular preform and the solidifiedplastic wax in the cells, is then pushed through a size reducing die atroom temperature. By partially pushing the composite body through a die,a body with the desired transition from large to small cells may beobtained. Afterwards, the wax is melted and removed; then the cellularbody is dried, fired and finished in the normal manner. A suitable waxfor this technique is a microcrystaline hydrocarbon wax with a highneedle penetration hardness (15+). This alternative drawdown techniqueis more fully disclosed in commonly assigned U.S. Patent Application No.60/068,230, incorporated herein by reference.

FIG. 1 shows a capillary reservoir device 10 that is the subject of thepresent invention. In a preferred embodiment, the device ideallycomprises a matrix of square channels 12, 100 channels along each outerwall 14 of the structure and 10,000 in total. The top of the device isthe fluid loading or input end 16 of the device. The exposed face of theinput end shall be called the input face. Each side of the input end 16of the device is approximately 112.5 mm. The surface area of the entireinput face, in this embodiment, is approximately 12,656 mm². Thestructure has been redrawn such that the length of each side on theoutput end 18 of the matrix is approximately 22 mm. The exposed face ofthe output end shall be called the output face. The surface area of theoutput face is approximately 484 mm². Each channel 12 within the device10 is self contained and decreases in cross sectional area inapproximate proportion to the decrease in total cross sectional surfacearea. Thereby, a channel having a width or pitch of 1.125 mm at the topsurface, as in FIG. 1, has a width or pitch of approximately 0.22 mm atthe bottom surface. The surface area of a cross-section of oneindividual channel as a proportion of the cross sectional area of aperpendicular plane taken at any point along the height of the verticalstanding device is approximately constant. Wall thickness may increaseslightly as a proportion of the total cross sectional area as the deviceis redrawn, but the number of channels is constant as well as therelative position of each channel in the matrix as defined by theon-center channel to channel pitch. Put another way, the device has aplurality of open ended channels extending from an input face to anoutput face wherein at least along a predetermined length, each channeldecreases equally in diameter, cross sectional area, and wall thickness.

Another alternative for making a capillary reservoir device is to etchor press channels in a surface of a plurality of slabs, pile the slabsone upon another forming a block having a plurality of channels formedtherethrough, fusing the slabs, and redrawing the entire structure.Creating a preform by this method is shown in FIGS. 22 and 23. FIG. 22shows a cross-sectional view of a portion of a slab 130. The slab 130has a plurality of evenly spaced parallel channels 132 formed into a topsurface 134. The channels can be made by any of a variety of knownmethods. If the material is glass, the channels may be etched, pressed,or created by precision rolling. If the material is a polymer, the slabmay be formed by injection molding techniques, for example. FIG. 23shows a partial cross sectional view of a plurality of slabs 130 piledone on another. The bottom surface 136 of each slab 130 serves to closethe channels 132 of the slab immediately beneath it. A top piece 138without channels seals the channels of the topmost slab. The entireconstruct is then heated to a temperature such that the slabs fusetogether thereby creating a block 140 capable of being redrawn as shownin FIG. 24. Blocks having any number of channels having any sizediameter or shape may be formed using this technique.

Virtually any block made from a thermoplastic material having aplurality of parallel channels formed therethrough may be redrawn inorder to form the device of the present invention.

It should be noted that an alternative method for making a capillaryreservoir device is to bind together a plurality of individual tubes orcapillaries. The tubes may be bound together into a bundle having anynumber of tubes. The bundle is then redrawn and finished in the samefashion as an extruded and redrawn block. FIG. 2 shows the output end 20of such a bundle of capillary tubes 22 after redraw. The tubes 22 servethe same function as the channels 12 of the device of FIG. 1. But forspecific references to figures, the terms channel and tube are analogoushereinafter while describing the device.

As an example to demonstrate feasibility, 22 tubes 22 were bondedtogether in rows of 7, 8 and 7 tubes. The matrix of 9 mm tubes was thenredrawn such that tube to tube center spacing became 350 μm, and thediameter of the capillary output opening in each tube was 180 μm.

The planar cut that exposes the output face of the device of either FIG.1 or FIG. 2, is preferably non-wetting. For example, in FIG. 2, the tubeinterior 24 preferably has a wetting surface, while the tube ends 26 arepreferably non-wetting. Similarly, the interior walls of the channels 12of the device of FIG. 1 are wetting, while the wall ends arenon-wetting. Because of the wetting channel interior and non-wetting endof each channel, droplets of liquid tend to bead on the end of eachchannel. Further, the non-wetting surface of the entire output plane ofthe device prevents crosstalk between channels at the output end.

Whether the device is made from a redraw of an extruded block orassembled block, or from bonded capillary tubes, the wettingcharacteristics of the output face may be obtained in the same way. Toobtain the wettability characteristics of the output face in a devicemade of a material that is only moderately wetting, such as polystyreneis to water, or non-wetting such as polyolefins such as polyethylene andpolypropylene are to water, wettability can be improved with oxidizingtreatments. For example, oxidizing chemical etchants such as sulfuric orchromic acids may be introduced to the channel interiors. One way ofsubjecting the channel interiors to the oxidizing etchant, or any otherliquid that will coat the interior channel walls is illustrated in FIGS.3-5. FIG. 3 illustrates how liquid 28 from a reservoir 30 coats theinterior 24 of the tubes 22 on the output end 20 of the device of FIG.2. The device is next sliced in a direction perpendicular to thechannels' length with a dicing machine as shown in FIG. 4. The dicingexposes the natural non-wetting or less wetting output face of thepolymer. FIG. 4 illustrates a planar cut of the output end 20 of thedevice of FIG. 2 being made with a dicing machine 32. The cut exposestube ends 26 that are non-wetting, while the tube interior 24 remainswetting due to the coating received from liquid 28 within the reservoir30. The cut tube fragments 34 are discarded.

With a device made of a naturally wetting material, such as glass is towater, the output portion of the device which has been cut and finishedmay be pressed against a rubber stamp coated with a non-wetting coating,for example a silane having a CF₃ termination, octadecyltriethoxysilane(OTS), or polydimethylsiloxane (PDMS). The silane is transferred to theoutput face of the device, making the surface non-wetting. The interiorof the channels made of glass are naturally wetting. Alternatively, theoutput end may be dipped into a solution that imparts non-wettingcharacteristics such as fluorodecyltrichlorosilane solution, forexample, while gas flow is injected into the input end of the capillaryarray to prevent the solution from entering the channel interiors. Thisway, output face obtains a non-wetting characteristic, while the channelinteriors remain uncoated, and thereby retain their wettingcharacteristic.

Once formed, the operation of a device whether made of an organicpolymer or glass is substantially the same. In operation, fluid isloaded into the input end of the device. The input is compatible withmacroscopic fluid loading, and loading may be accomplished through anyvariety of known means including: pipette, syringe, pumps, multiplepipette or syringe systems, funnels, etc. Preferably, the center spacingbetween channels at the input end preferably corresponds to the centerspacing of a multiwell plate, a 1536 well plate for example. This way,fluids contained individually in each well of a 1536 well plate may beloaded by forcing the fluid through a hole in the bottom of each well inthe 1536 well plate into corresponding channels in the capillaryreservoir device. Each channel is self contained, so potentially 10,000different fluids can be loaded into the device. It is important to notethat the number of channels is entirely variable and the number 10,000was chosen simply as an example of a preferred embodiment.

Each channel's volume is determined by its internal dimensions includingthe height of the device. Ideally, each channel will contain 5 to 500microliters, but any volume is possible as determined by the variabledimensions: pitch of channel at top and bottom, and height of thedevice.

Ideally, the pitch of the channel at the output end is such that liquidwill be retained within each channel by capillary force. This way,liquid will remain in each channel until forced out by some externalforce. One way of forcing liquid through the capillary is though the useof photon pressure to valve the capillaries. In such an embodiment, andas described in French patent application, an optical pulse is sentthrough an optical fiber and a microlens through a window in eachcapillary. The photonic pulse elicits the formation of a droplet fromthe output end of each capillary that has been designated. Other methodsfor extracting a droplet from the output end of the capillaries include:external pressure such as a vacuum at the output or a positive pressureat the input end, mechanical pressure, acoustic pressure, magneticpressure, heating, or any other method that would provide constantdisplacement among the channels.

In a preferred embodiment, each channel is filled with a differentbinding entity held within a liquid matrix. “Binding entities” aregenerally termed as a biological or synthetic molecule having a specificaffinity for another molecule, through covalent bonding or non-covalentbonding. Preferably, a specific binding entity contains (either bynature or by modification) a functional chemical group (primary amine,sulfhydryl, aldehyde, etc.), a common sequence (nucleic acids), anepitope (antibodies), a hapten, or a ligand, that allows it tocovalently react or non-covalently bond to a common function group onthe surface of a substrate. Specific binding entities include, but arenot limited to: deoxyribonucleic acids (DNA), ribonucleic acids (RNA),synthetic oligonucleotides, antibodies, proteins, peptides, lectins,modified polysaccharides, synthetic composite macromolecules,functionalized nanostructures, synthetic polymers, modified/blockednucleotides/nucleosides, modified/blocked amino acids, fluorophores,chromophores, ligands, chelates and haptens. The term “biomolecule” and“binding entity” are interchangeable for purposes of this disclosure.

It should be noted that application for this device are not limited tobiological materials, but may extend to any chemistry capable of beingin liquid form or in a suspension including but not limited toemulsions, particle suspensions, and coacervates. In fact, a reservoirdevice made from PYREX is capable of printing an array of a liquid thathas been heated up to 500° C. This has potential implications inchemical applications such as printing room temperature semiconductors,dispensing hot pigments or hot waxes, and other nanoengineeredmicrocomponents.

The liquid that contains the binding entity is preferably an acrylamidemonomer, but may be any biocompatible polymerizable material. Theacrylamide provides the necessary cross-linking required for DNA orother biomolecule immobilization. In a preferred embodiment, 10,000different acrylamide solutions, each containing an oligimer of slightlydifferent nucleotide sequence are loaded into each channel through meansof a multiwell plate as previously described, by multiwell pipette,syringe, etc. Droplets will be elicited from each channel simultaneouslyby means of photon pressure, external pressure, etc. The drops arecontacted against the substrate and thereby deposited. Next, theacrylamide is preferably polymerized by ultra-violet radiationimmediately after deposition onto the substrate. The resultant array ofpolymerized drops is characterized in that the pitch between drops onthe substrate is substantially identical to the pitch between channelson the output face of the device. Each droplet occupies an identifiableposition in the overall array, and the biomolecules within each drop arecovalently bound to the polymerized acrylamide. The biomolecules, inthis embodiment—oligonucleotides, are covalently bound to thecodeposited polymerized acrylamide.

Any conceivable substrate may be employed in this invention. Thesubstrate may be biological, nonbiological, organic, inorganic, or acombination of any of these, existing as particles, strands,precipitates, gels, sheets, tubing, spheres, beads, porous beads,containers, capillaries, pads, slices, films, plates, slides, membranes,etc. The substrate may have any convenient shape, such as a disc,square, rectangle, sphere, etc. The substrate is preferably flat, butmay take on a variety of alternative surface configurations. Forexample, the substrate may contain raised or depressed regions on whichliquid is deposited. Further, the substrate may be glass, polymer ormembrane into which channels have been etched; or it may contain regionsthat have been made porous by means of a chemical etchant. The substrateand its surface preferably form a rigid support on which a liquid withthe appropriate surface energy and containing a binding entity can bedeposited, and which is preferably functionalized with an organosilanesuch as gamma-aminopropyl triethoxysilane ormethacryloxypropyltriethoxysilane, for example.

In a preferred embodiment, the substrate is flat glass, preferably aborosilicate glass having surface relief features of less than 10nanometers. Although a non-patterned plate is preferred for dropletalignment issues, the surface of the glass substrate may be coated with,a non-wetting agent such as fluorodecyltrichlorosilane orocyadecyltrichlorosilane, for example. The coating may be selectivelyremoved by using known methods of photoresist or selectively appliedusing masking techniques. Preferably, an array of positions that areuncoated and thereby wetting is presented. The spacing in thewetting/non-wetting positional array preferably corresponds to thespacing between channels on the output face of the capillary reservoirdevice. This way, drops need only contact the exposed wetting positionson the substrate for drop transfer. The drops are drawn into the centerof the wetting position by physical and chemical means. Crosstalk iseliminated by the wetting characteristics of the substrate.Alternatively, a patterned etching process may create positions withinthe substrate and below the substrate surface that form a matrix ofporous glass regions which may also serve to eliminate the potential forcrosstalk. Drops may be deposited within the porous regions whichpreferably align with the channel spacing on the output face of thecapillary reservoir device.

Printing Methods

Printing a matrix of droplets of acrylamide containing oligonucleotidesdirectly from the capillary reservoir device, and with a spacing of lessthan 200 μm apart, may require a specific process in order to reduce thepotential of neighboring droplets from spreading and combining, i.e.crosstalk. The printing process comprises the steps of providing acapillary reservoir device having a non-wetting fluorinated treatment onthe output plane and the sidewalls; filling at least one channel of thecapillary reservoir device with an acrylamide/biomolecule mixedsolution; providing a functionalized glass substrate, for example asubstrate coated with an organosilane such asmethacryloxypropyltriethoxysilane; and, transferring a droplet from theoutput of each channel in the device by contact with the substrate in anenvironment of zero or negative capillary pressure.

An acrylamide/oligonucleotide solution has a medium range surfacetension of approximately 52 mN.m⁻1 and a relatively low contact angle onglass substrates functionalized with methacryloxypropyltriethoxysilane,for example, of approximately 50 degrees. Contact angle is a directmeasure of surface energy. With a contact angle of 50 degrees, it is notpossible to avoid droplet mixing between individual droplets spaced 100μm or less apart on the substrate prior to curing. Furthermore, contactangles below 90 degrees create, upon transfer, a positive capillarypressure between the capillary reservoir device and the glass substratewhich causes the oligonucleotides in the liquid droplets to spread intothe gap separating the output end of the capillary reservoir device andthe substrate. Therefore, a negative or zero capillary pressureenvironment is preferred in order to limit crosstalk during droptransfer. In order to achieve a negative or zero capillary pressureenvironment between the device and the substrate, contact angles equalto or higher than 90 degrees are required on both the output face of thereservoir device and the substrate surface. For the capillary reservoirdevice, the fluorination treatment previously described satisfies thiscondition.

For the substrate, the proper contact angle may be achieved byaccomplishing the drop transfer from the capillary device to thefunctionalized substrate in an environmental immiscible liquid mediumother than air. Because the oligonucleotides are based in an aqueoussolution, alkanes or hydrocarbons satisfy the condition ofimmiscibility. As an example, the contact angle of the aminefunctionalized substrate with respect to the oligonucleotide/acrylamidesolution is increased from 50 degrees in air to 100 degrees in dodecane.Under these conditions, the spreading of the oligonucleotide/acrylamidedroplets is limited and the capillary pressure is negative. By immersingthe substrate in the hydrocarbonated liquid, the surface tension of thesubstrate is substantially reduced compared to air. The contact angle ofthe oligonucleotide/acrylamide solution to the channels of the reservoirdevice is also increased, thereby creating favorable conditions for thedroplet transfer.

After transfer, the immiscible liquid environment further provides anoxygen free environment for the oligonucleotide/acrylamide droplets tobe cured to the substrate. This is an important advantage over open airtransfers because the acrylamide polymerization is very sensitive tooxygen inhibition In order to increase the contact angle of thefunctionalized substrate with respect to the oligonucleotide/acrylamidesolution to 90 degrees or more, droplet transfer in an immiscible liquidmedium having a surface tension of about 35 mN. m⁻¹ at 20° C. ispreferred.

It has been observed that it may be advantageous to store thefunctionalized substrate for one hour in the hydrocarbon environmentbefore initiating droplet transfer from the capillary reservoir device.This step allows for the use of hydrocarbonated liquids having a surfacetension, γ, of 25 mN. m⁻¹ or greater at 20° C. Table 4 is anon-exclusive listing of hydrocarbons that may be used to provide theproper environment for the oligonucleotide/acrylamide droplet depositiononto a substrate.

TABLE 4 Hydrocarbon Surface Tension γ at 20° C. (mN. m⁻¹) Dodecane 25.4Tridecane 26.0 Tetradecane 26.6 Pentadecane 27.1 Hexadecane 27.5Cyclohexane 25.2 Decahyronaphthalene 31.1 Bromonaphthalene 44.4

It should be noted that the process of drop transfer from one medium toanother in an environmental immiscible liquid may be performed for anynumber of differing droplet chemistries and substrates, and may varyaccording to the chemistry of the droplet as well as the chemistry ofthe substrate. It may be used wherever low surface tension liquids arebeing transferred in order to prevent the droplet spreading on thesubstrate. After the drop is cured, the plate can be warmed up toapproximately 60-65° C. in order to evaporate the solvent and/or theenvironmental hydrocarbon.

One way of avoiding the need for a negative capillary pressureenvironment is to create a reservoir device that is designed in such away as to maintain a constant fluid level at the output end. Inexplaining the basic concept of how this may be accomplished, the focuswill be upon a single channel in the device. In this embodiment, thereservoir is bent after redraw such that the output face and input faceare in the same horizontal plane and the entire device is U-shaped.Further, each individual channel is U-shaped, as shown in FIG. 14 whichis a cross sectional view of one channel from the device, and has apredetermined radius (r₂) at the input end 82 and a predetermined radius(r₁) at the output end 84. The liquid may either bead on the output ofthe channel or form a meniscus within the channel depending on thecapillary pressure, density of the liquid and head height as determinedby the contact angle. For purposes of this disclosure, whether theliquid beads or not is not important, but in the following examples, theliquid forms a meniscus in the channel.

A pin from a typographic pin plate, for example, is inserted into thechannel at the output end of the device in order to pick up a liquiddroplet, which in turn is contacted to a substrate in creating thearray.

As can be observed, r₂ is greater than r₁. Liquid, such as DNA probesolution to be printed, is loaded into the input end 82 of the channel.A pin having a radius that is slightly smaller than r₁ contacts theliquid by entering the output end 84 of the channel. A liquid droplet,of volume v, is elicited from the channel by surface tension on the pinsurface and transferred to a substrate. Due to capillary pressure, thelevel of liquid in the channel does not drop on the output end. Thelevel of liquid on the input end of the device drops by the volume ofthe drop that has been removed, while the level of the liquid at theoutput end of the device remains the same. This phenomenon is a resultof the capillary pressure between the output end of the channel and theinput end. The capillary pressure is equal to 2γ(1/r₁−1/r₂), wherer₁<r₂, and where γ is the liquid surface tension. The pressure allowsthe removal of a volume of liquid, v, at the output end of the channel,without affecting the level of the liquid at the output end. Liquid willbe reduced on the input end of the device, while remaining constant onthe output end of the device, until the difference in height between thetwo ends of the capillary, H, reaches the capillary height defined by:2γ/ρg (1/r₁−1r₂), where ρ is the liquid density and g represents gravity(9.81 m.s⁻²). The total volume, V, that may be extracted from thechannel before the liquid level on the output end begins to drop isgiven by the equation: V=2πr₂ ²γ(1/r₁−1/r₂)/ρg. The number of possibletransfers to a typographic pin from this channel is equal to V/v.

It should be noted that it is not necessary that the input and andoutput end be in the same horizontal plane. The output end can be lowerthan the input end, but the distance between the two ends, h, must beless than the capillary height, H. When the output and input ends are inthe same plane (h=0), V is at a maximum.

As an example, assuming the input end and the output end are in the sameplane (h=0), r₁=50 μm, r₂=300 μm, γ=50×10⁻³ N.m^(−1,) and ρ=10³kg/m³,then the volume of DNA probe solution available, V, while retaining aconstant level in the output end of the channel, is equal to 48 μl. Ifthe typographic plate used to transfer liquid from the output end of thedevice to a substrate plate has pins having a radius in the order of 40μm, the volume of individual droplets will be 80 pl. Therefore, thechannel will allow for 600,000 pin transfers of liquid while the liquidlevel on the output end of the channel remains constant.

Obviously, the complete reservoir device would be comprised of aplurality of channels having the described U shape. The number ofcapillaries will correspond to the number of sites in the desired array.An example of a printing tool 90 that employs the bent device is shownin FIG. 15. The bent reservoir device 92 is housed in a boxed unit 94such that the output face 96 and input face 98 of the device are inapproximately the same plane. A typographic pin array 100 having amatrix of pins aligned such that each pin from the matrix fits into acorresponding channel from the output face 96 of the reservoir device 92is mounted on a flexible stainless steel flextem 102. A string 104attaches a lever 106 with the top surface of the flextem 102 such thatwhen the lever is actuated, the pin plate 100 contacts the output face96 of the device such that each pin enters each channel, contacts theliquid therein and is thereafter removed. FIG. 16 shows a crosssectional portion of the pin plate 100 of FIG. 15 as it interacts withthe output face 96 of the device. Individual pins 101 contact liquid 103from a plurality of channels 105. The pin plate 100 is removed from thechannels 105 pulling a drop 107 of liquid from each of the channels; thedrops are affixed to the ends of the pins 101, as shown in FIG. 17.After the drop 107 is removed, the liquid level remains at the top ofeach channel 105. A properly prepared substrate is then placed under thepin plate 100; after which, the pin plate is contacted to the substratesurface thereby depositing an array of drops. FIG. 18 shows a partialcross sectional view of a substrate 108 having a plurality of drops 110that have been deposited thereon by the pin plate 100.

It is not necessary to employ a U-shaped structure in order to obtain aconstant level on output end of the reservoir. A cross section of theprinting tool of FIG. 15 containing the U-shaped reservoir device isshown in FIG. 19. Two alternative capillary reservoir designs are shownin FIGS. 20-21. The U-shaped reservoir 92 of FIG. 19 having an inputface 98 radius of 300 μm, an output face 96 radius of 50 μm, and alength of 200-400 mm, is ideal for containing 50-100 μl of liquid andprinting approximately 500,000-1,000,000 drops of approximately 80pl/drop. FIG. 20 is an example of a reservoir device having a conicaldesign 120 whereby the input ends of the channels making up the deviceare filled with the chosen liquid mixture. The device is then flippedover so that the output end 122 of the device faces upward. The liquidwill be retained within the channels due to capillary pressure, and theliquid level will remain constant at the output end of the device evenafter droplets have been drawn from the channel. In this design,assuming the same output and input face radius as above, but having achannel length of 20-50 mm, each capillary reservoir (channel) contains2-10 μl of printable liquid, which translates into approximately between20,000-100,000 drops of 80 pl/drop.

FIG. 21 shows another alternative design of the device. This designallows for greater volume storage than the channel design of FIG. 19,but less than is allowed in the U-shaped design. This L-shaped device124 works substantially in the same way in that each reservoir is filledthrough the input face 126 of the device and droplets are drawn from theoutput end 128 of the device, by pin plate for example. As in theexamples above, the liquid level at the output end remains constant. Inthis design, assuming the same output and input face radius as above,but having a channel length of 50-200 mm each capillary reservoir(channel) contains 10-50 μl of printable liquid, which translates intoapproximately between 100,000-500,000 drops of 80 pl/drop.

It should be noted however, that smaller volumes of liquid may be loadedinto these devices; the liquid will be driven by capillary forces to theoutput end of the device. The stated ranges are only suggested volumesand are not intended to be limiting to each embodiment.

Printing Beads

Often, biomolecules such as oligonucleotides or peptides are synthesizedon low cross-linked polystyrene beads or other polymeric supports bymethods described and referenced by S. R. Wilson and A. W. Czarnik inCombinatorial Chemistry, Synthesis and Application (1997). This type ofsynthesis is called solid phase synthesis and it is by this means thatextremely large libraries of biomolucules or other sequentially orcombinatorially produced molecules can be synthesized and identified.The synthesized biomolecules are routinely cleaved from the bead at thecompletion of the synthesis process.

In this embodiment, molecules that have been synthesized by solid phasesynthesis are not cleaved from the support beads. Instead, they areincorporated, in suspension, along with an appropriate solvent in orderto create a printable liquid. In order to retain the ability to remainin suspension while still minimizing any potential steric interactionproblems, the biomolecules are preferably synthesized on beads that arebetween 0.3 and 0.6 μm in diameter.

The suspension is printed onto a substrate by the method disclosedabove. Preferably and by means of an example, the substrate is glasswith a vinyl silane coating and the beads are vinyl benzene cross-linkedin divinyl benzene. Each channel of the capillary reservoir device isfilled with a different known biomolecule covalently attached to aplurality of beads such that, within any one channel, there are aplurality of identical biomolecules attached to a plurality of beads.The suspensions containing the beads are printed into an array atpredetermined attachment positions either on the substrate surface, orwithin microwells or channels within the substrate. Once printed, thevinyl group from the vinyl silane covalently reacts with the styrene(vinyl benzene) in the bead thereby immobilizing the bead to thesubstrate surface. The molecules themselves remain immobilized on thebead. It is contemplated that other materials may be used for the beadsand for the substrate in order to take advantage of such a covalentbead-substrate immobilization interaction.

In an alternative embodiment, molecules are synthesized on beads thatare sized such that only one bead at a time will fit through the outputof any individual channel of the device. This way, a single bead may beprinted at each position on the array. Each individual bead contains atleast one molecule attached thereto, while the bead itself attaches tothe substrate. In this embodiment, the sizing of the bead is dependenton the diameter of the channels at the output end of the capillaryreservoir device that is employed in the printing.

In yet another embodiment, non-reacted beads are deposited on asubstrate in an array. Combinatorial or sequential synthesis can then beperformed on the immobilized beads.

Slice Array

Another embodiment of the present invention involves a technique thateliminates the need for liquid handling as between the capillaryreservoir device and a substrate. In this embodiment, a capillaryreservoir device that preferably has 1,000 or more channels and ispreferably comprised of an organic polymer such as polystyrene, isredrawn down (as shown in FIG. 6) to a predetermined size and elongatedsuch that a reduced linear portion 40 of substantially uniform crosssectional size is created at the outlet end 42. FIG. 5 shows the initialextrusion of a preform block 44, through a die 40, and prior to redraw.Each channel of the resultant redrawn device 48 is then filled with aliquid. Each liquid is a different mixture of a particular bindingentity and a thermally activated curing polymer such as an epoxy resin(EPON). As an example, each channel may contain a different aminatedoligonucleotide or cDNA which is combined with the epoxy resin. Anepoxide group from the epoxy resin will covalently react with the aminecreating a crosslinked polymer network. A different knownoligonucleotide or cDNA fragment is selected for each individual channeland combined with the epoxy. The various mixtures are entered into themany channels, the entire device is cured, for example in a 6 hour cycleat 40° C., or more preferably 2 days at room temperature in order tolimit gas production caused by the polymerization reaction. FIG. 7 showsthe device of FIG. 6 undergoing a curing step. The curing may beperformed by gamma radiation, blue light, temperature activation, orroom temperature curing, for example.

After curing, the reduced sized portion 40 is cut from the rest of thedevice and preferably frozen down to −40° C., below the polymer glasstransition temperature. The freezing step makes the epoxy matrix andpolymer brittle thereby facilitating a clear cut by fracturing. Cuttingby fracturing reduces the chance of crosstalk contamination as betweenneighboring channels as the blade passes through. Further, deformationor distortion of the array is prevented with this type of cuttingtechnique.

The reduced size portion 40 may then be chopped into blocks 50 as shownin FIG. 8. FIG. 9 shows very fine slices 54 being cut from a frozenblock 50 with a tomography cutting tool 52, such as a diamond blade orglass blade, for example. Each slice 54 is preferably approximatelybetween 4 and 10 μm in thickness, although any slice thickness may bepossible. Each slice also contains 10,000 different binding entitiessuspended in the cured epoxy resin matrix as a result of the channelfilling. The slice takes the form of a sheet comprising a latticenetwork formed by the channel walls and defining a plurality ofcontainment spaces each having sidewalls and an open top and bottom, anda different known binding entity occupying each containment space.

After the slicing, the slice 54 is bonded to a preferably flat substrateslide 56, as shown in FIG. 10, preferably made of either glass or anorganic polymer, by means of ultrasonic welding or gluing, for example.The walls of the channels serve as boundaries for elimination ofcrosstalk between samples. Further, the material of the capillaryreservoir device is preferably opaque, and more preferably black. Thisway, optical crosstalk that often results as a consequence offluorometric, chemiluminescent or calorimetric assays may be reduced asbetween different samples. Bar coding 57 may be employed as a means ofrecording the contents of each well or position on the array. Properalignment of the slice on the substrate can be assured by a feature suchas a beveled edge (not shown).

Once bound to the substrate, the slide may be packaged for transport andsubsequent use in any variety of research or diagnostic procedures.

It should be noted that as in the method described above, the liquidsuspension including synthesized biomolecules covalently attached tobeads may be used along with the resin to fill the channels and becomepart of the polymer network upon curing.

Assay Plate Reformatting

Another embodiment of the present invention involves its use inreformatting assay plates. For many years, multi-well laboratory plateshave been manufactured in configurations ranging from 1 well to 96wells. The wells of multi-well plates are typically used as reactionvessels for performing various tests, growing tissue cultures, screeningdrugs, or performing analytical and diagnostic functions. Industrystandard multi-well plates are laid out with 96 wells in an 8×12 matrix(mutually perpendicular 8 and 12 well rows). In addition, the height,length and width of the 96-well plates are standardized. Thisstandardization has resulted in the development of a large array ofauxiliary equipment specifically developed for 96-well formats. Theequipment includes devices that load and unload precise volumes ofliquid in multiples of 8, 12, or 96 wells at a time. Recently, as samplesizes have been reduced to microliter levels and the demand for agreater number of tests per plate has increased, the number of wells ona plate have likewise increased, e.g. from 384 wells to 1536 wells andabove. In order to accommodate the existing auxiliary equipment, thestandard plate footprint has remained the same, while the well densityhas increased. The higher density plates predominately have a number ofwells that are a multiple of the standard 96. These plates have wellspacing that is fractionally based on the center well spacing of a 96well plate.

One challenge that has presented scientists is how to efficiently andquickly transfer samples that have been prepared in a comparativelylower density plate, such as a 96 well plate, to a plate ofcomparatively more wells per same unit area, such as a 1536 well plate,for example. Referring to FIG. 11, a redrawn capillary device can beformed having such dimensions that the transfer form a 96 well plate toa 1536 well plate can occur quickly and easily. The input end 60 of thedevice is sized approximately to the dimensions of an industry standard96 well plate (3.370 inches by 5.035 inches). 96 channels 62 are spacedin an 8×12 matrix (mutually perpendicular 8 and 12 channel rows). Thechannels align with the wells of the 96 well plate which are spacedapproximately 0.355 inches on center. The device is redrawn in a 16 to 1reduction such that the center spacing between channels on the outputend 64 approximately equates to the center spacing between wells of a1536 well plate (0.089 inches). The wells of a 1536 well plate arespaced in a 48×32 matrix (mutually perpendicular 48 and 32 well rows).It would take 16 of the 96 well plates to fill a plate having 1536wells. The samples that have been transferred will have an orderedorientation. In other words, the 1536 well plate can be divided into amatrix of 4 rows and 4 columns, each location in the matrix containingthe samples from a single 96 well plate in their original orientation.In FIG. 11, a 96 well filter plate 68 is aligned over the input end 60of the device. Each well from the 96 well filter plate 68 aligns with achannel from the device. Samples from the 96 well filter plate areloaded into each channel 62. The output end 64 of the device is thenlocated over a portion of a 1536 well plate 66 as shown in FIG. 12 suchthat channels on the output end 64 align with wells of the 1536 wellplate. Sample is then expelled from each channel into individual wellsof the plate 66.

The output end of the device may be fitted with multiple syringe needlesor pipette tips to facilitate transfer.

Use of this transfer method is especially beneficial for dispensinglarge numbers of samples in compiling multiple copies of a compoundlibrary, for example.

The capillary device used as a transfer tool works equally well fortransfers between a 96 well plate and a 384 well plate. The reductionduring redraw in this case is 4 to 1. The 384 well plate can contain thesamples from four 96 well plates in a 2×2 matrix. The capillary devicemay be employed to deliver samples from a multiwell plate of having anynumber of wells to a plate having a larger number of well per unit area.The device may even be employed in the reverse, to transfer samples froma 1536 well plate to a 96 well plate, for example.

Further, it can be conceived that sealing means can be provided that cancover both the loading or input end of the device and the output end ofthe device. Such a seal will prevent evaporation and create favorablestorage conditions. Examples of sealing means include snap-on lids, heatsealed wraps, rubber mats, pressure sealing tape, or any other sealingmechanism known in the art.

Further, the reformatting tool can be used as between a 384 well plateand a 1536 well plate; or even from a 1536 to a flat substrate. It isconceived that the reformatting tool can be used as between any twoplates of differing well density, so long as the matrix pattern definedby the pitch between wells in the plates is scaled.

It can be further conceived that semi-conductor micro-fabrication may beaccomplished using the redraw and printing technology disclosed herein.

Although the invention has been described in detail for the purpose ofillustration, it is understood that such detail is solely for thatpurpose and variations can be made therein by those skilled in the artwithout departing from the spirit and scope of the invention which isdefined by the following claims.

What is claimed is:
 1. A method for transferring individual droplets of liquid to a substrate, comprising the steps of: providing a reservoir device having a plurality of individual passages, each having an output end; positioning a transfer device having an array of pins extending therefrom such that the pins face the output ends of the passages; contacting the pins with liquid from the corresponding passages to transfer droplets of liquid from the corresponding passages to the pins; maintaining liquid that remains in the passages after transfer of the droplets of liquid to the pins, at the output ends of the passages via capillary force; and moving the pins relative to the substrate to transfer the droplets of liquid onto the substrate.
 2. The method of claim 1, wherein the contacting step includes moving the pins into contact with liquid from the corresponding passages.
 3. The method of claim 1, wherein the maintaining step includes maintaining beads of liquid at the output ends.
 4. The method of claim 1, wherein the maintaining step includes forming a meniscus of liquid at the output ends.
 5. The method as claimed in claim 1, wherein the moving step includes moving the pins a sufficient distance such that the droplets of liquid directly contact the substrate.
 6. The method as claimed in claim 1, wherein the transfer device is a typographic pin plate.
 7. The method as claimed in claim 1, wherein the passages each have an input end, and wherein the method further comprises the step of dropping the level of liquid at the input ends of the passages by a volume of liquid transferred to the pins, while maintaining the level of liquid at the output ends of the passages.
 8. A method for transferring individual droplets of liquid to a substrate, comprising the steps of: providing a reservoir device having a plurality of individual passages, each having an output end; positioning a transfer device having an array of pins extending therefrom such that the pins face the output ends of the passages; contacting the pins with liquid from the corresponding passages to transfer droplets of liquid from the corresponding passages to the pins; maintaining liquid at the output ends of the passages via capillary force; and moving the pins relative to the substrate to transfer the droplets of liquid onto the substrate.
 9. The method of claim 8, wherein the providing step further includes cutting the redrawn portion in a direction perpendicular to a longitudinal direction of the passages to expose a face having a cross sectional area less than a cross sectional area of the extruded honeycomb structure.
 10. A method for transferring individual droplets of liquid to a substrate, comprising the steps of: providing a reservoir device having a plurality of individual passages, each having an output end; positioning a transfer device having an array of pins extending therefrom such that the pins face the output ends of the passages; contacting the pins with liquid from the corresponding passages to transfer droplets of liquid from the corresponding passages to the pins; maintaining liquid at the output ends of the passages via capillary force; and moving the pins relative to the substrate to transfer the droplets of liquid onto the substrate, wherein the providing step includes extruding material through a die thereby forming a block having the passages, and redrawing the block such that a circumference of the block is reduced.
 11. A method for transferring individual droplets of liquid to a substrate, comprising the steps of: providing a reservoir device having a plurality of individual passages, each having an output end; positioning a transfer device having an array of pins extending therefrom such that the pins are opposite the output ends of the passages; contacting the pins with liquid from the corresponding passages to transfer droplets of liquid from the corresponding passages to the pins; maintaining liquid at the output ends of the passages via capillary force; and moving the pins relative to the substrate to transfer the droplets of liquid onto the substrate.
 12. A method for transferring individual droplets of liquid to a substrate, comprising the steps of: providing a reservoir device having a plurality of individual passages, each having an output end and an input end of different cross sectional area than the output end, a ratio of the cross sectional area of one of the passages relative to a cross sectional area of the reservoir device is substantially identical at a liquid-input end of the reservoir device and a liquid-output end of the reservoir device; positioning a transfer device having an array of pins extending therefrom such that the pins face the output ends of the passages; contacting the pins with liquid from the corresponding passages to transfer droplets of liquid from the corresponding passages to the pins; maintaining liquid at the output ends of the passages via capillary force; and moving the pins relative to the substrate to transfer the droplets of liquid onto the substrate.
 13. An apparatus for transferring individual droplets of liquid to a substrate, comprising: a reservoir device having a plurality of individual passages, each of the passages having an output end; and a transfer device having an array of pins extending therefrom, the transfer device positionable such that the pins face the output ends of the passages, the pins being adapted to receive liquid from corresponding passages for transfer of individual droplets of liquid to the substrate, wherein the passages are configured to retain liquid that remains in the passages after the pins receive liquid, at the output ends of the passages via capillary force.
 14. The apparatus as claimed in claim 13, further comprising a drive member adapted to move the pins relative to the corresponding passages.
 15. The apparatus as claimed in claim 14, wherein the drive member moves the pins into the output ends of the corresponding passages.
 16. The apparatus as claimed in claim 13, wherein the passages are configured to prevent fluid communication therebetween.
 17. The apparatus as claimed in claim 13, wherein the reservoir device is approximately one inch square at the output ends of the passages.
 18. The apparatus as claimed in claim 13, wherein the reservoir device has an input and an output in the same plane as the input.
 19. The apparatus as claimed in claim 13, wherein the passages of the reservoir device have an input end in the same plane as the output end.
 20. The apparatus as claimed in claim 13, wherein the pins are dimensioned to extend into the output ends of the corresponding passages.
 21. The apparatus as claimed in claim 13, wherein the pins have a radius less than 50 μm.
 22. The apparatus as claimed in claim 13, wherein the pins have a radius of about 40 μm.
 23. The apparatus as claimed in claim 13, further comprising a boxed unit in which the reservoir device is mounted.
 24. The apparatus as claimed in claim 14, wherein the pins are mounted on a flexible mount, and the drive member is coupled to the flexible mount to flex the pins toward the output ends of the corresponding passages.
 25. The apparatus as claimed in claim 24, wherein the pins are dimensioned to enter into the corresponding passages.
 26. The apparatus as claimed in claim 13, wherein the passages have interior walls having a wetting surface, and the output ends of the passages have a non-wetting end surface.
 27. The apparatus as claimed in claim 13, wherein the reservoir device is comprised of an organic polymer.
 28. The apparatus as claimed in claim 13, wherein the reservoir device is comprised of an inorganic polymer.
 29. The apparatus as claimed in claim 28, wherein the inorganic polymer is glass.
 30. The apparatus as claimed in claim 13, wherein each passage is dimensioned to contain 5 to 500 microliters of liquid.
 31. The apparatus as claimed in claim 13, wherein the transfer device is a typographic pin plate.
 32. The apparatus as claimed in claim 13, wherein the passages each have an input end, and the passages are configured such that the level of liquid at the input ends of the passages drops by a volume of liquid received by the pins, while the level of liquid at the output ends of the passages is maintained.
 33. An apparatus for transferring individual droplets of liquid to a substrate, comprising: a reservoir device having a plurality of individual passages, each of the passages having an output end; and a transfer device having an array of pins extending therefrom, the transfer device positionable such that the pins face the output ends of the passages, the pins being adapted to receive liquid from corresponding passages for transfer of individual droplets of liquid to the substrate, wherein the passages are configured to retain liquid that remains in the passages after the pins receive liquid, at the output ends of the passages via capillary force, wherein the reservoir device has an input and an output in the same plane as the input, and wherein the reservoir device has a substantially U-shape.
 34. An apparatus for transferring individual droplets of liquid to a substrate, comprising: a reservoir device having a plurality of individual passages, each of the passages having an output end; and a transfer device having an array of pins extending therefrom, the transfer device positionable such that the pins face the output ends of the passages, the pins being adapted to receive liquid from corresponding passages for transfer of individual droplets of liquid to the substrate, wherein the passages are configured to retain liquid that remains in the passages after the pins receive liquid, at the output ends of the passages via capillary force, and wherein the reservoir device has an input and an output in a different plane from the input.
 35. The apparatus as claimed in claim 24, wherein the reservoir device has a substantially conical shape.
 36. The apparatus as claimed in claim 24, wherein the reservoir device has a substantially L-shape.
 37. An apparatus for transferring individual droplets of liquid to a substrate, comprising: a reservoir device having a plurality of individual passages, each of the passages having an output end; and a transfer device having an array of pins extending therefrom, the transfer device positionable such that the pins face the output ends of the passages, the pins being adapted to receive liquid from corresponding passages for transfer of individual droplets of liquid to the substrate, wherein the passages are configured to retain liquid that remains in the passages after the pins receive liquid, at the output ends of the passages via capillary force, wherein the passages of the reservoir device have an input end in the same plane as the output end, and wherein the passages of the reservoir device form a substantially U-shape.
 38. An apparatus for transferring individual droplets of liquid to a substrate, comprising: a reservoir device having a plurality of individual passages, each of the passages having an output end; and a transfer device having an array of pins extending therefrom, the transfer device positionable such that the pins face the output ends of the passages, the pins being adapted to receive liquid from corresponding passages for transfer of individual droplets of liquid to the substrate, wherein the passages are configured to retain liquid that remains in the passages after the pins receive liquid, at the output ends of the passages via capillary force, and wherein the passages of the reservoir device have an input end in a different plane from the output end.
 39. The apparatus as claimed in claim 38, wherein the passages of the reservoir device form a substantially conical shape.
 40. The apparatus as claimed in claim 38, wherein the passages of the reservoir device form a substantially L-shape.
 41. An apparatus for transferring individual droplets of liquid to a substrate, comprising: a reservoir device having a plurality of individual passages, each of the passages having an output end; and a transfer device having an array of pins extending therefrom, the transfer device positionable such that the pins face the output ends of the passages, the pins being adapted to receive liquid from corresponding passages for transfer of individual droplets of liquid to the substrate, wherein the passages are configured to retain liquid that remains in the passages after the pins receive liquid, at the output ends of the passages via capillary force, wherein the passages of the reservoir device have an input end in the same plane as the output end, and wherein the reservoir device contains approximately 10,000 individual passages.
 42. An apparatus for transferring individual droplets of liquid to a substrate, comprising: a reservoir device having a plurality of individual passages, each of the passages having an output end and an input end of different cross sectional area than the output end, a ratio of the cross sectional area of one of the passages relative to a cross sectional area of the reservoir device being substantially identical at a liquid-input end of the reservoir device and a liquid-output end of the reservoir device, the passages being configured to retain liquid at the output ends thereof via capillary force; and a transfer device having an array of pins extending therefrom, the transfer device positionable such that the pins face the output ends of the passages, the pins being adapted to receive liquid from corresponding passages for transfer of individual droplets of liquid to the substrate. 